FXX's 12-day marathon of every episode offers an opportunity to celebrate – and re-examine – TV's most enduring nuclear family.

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When "The Simpsons" debuted on Dec. 17, 1989, "The Cosby Show," then in the last of its amazing five-season run as the nation’s No. 1 show, ruled the airwaves. From the start, the animated and dysfunctional Simpson clan presented a very different take on American family life than the flesh-and-blood, high-achieving Huxtables. But the more enduring and defining legacy of Matt Groening’s creations came in turning a funhouse mirror on the popular culture of the past quarter century, part “Saturday Night Live”-style, but more like classic MAD magazine.

See for yourself starting Thursday, when Fox's FXX channel launches a round-the-clock, DVR-busting marathon of all 552 "Simpsons" episodes, broadcast in order, along with the 2007 theatrical movie inspired by the show. That’s a dozen days of “Simpsons” – or the length of an average visit to Moe's by Barney Gumble.

If that sounds like too much of a good thing – or of a dubious thing, like Duff beer, Krusty burgers and doughnuts (mmm… doughnuts!) – well, overindulgence is just "The Simpsons" way. The marathon, a prelude to the upcoming Simpsons World digital platform, offers an opportunity to shout woo-hoo! for a comedy classic – as well as trace the evolution of a show that starts its 26th season next month as the longest-running scripted primetime TV program in U.S. history.

Revisiting “Simpsons” episodes lets us relive great moments and discover others we might have missed the first time around – all while unlocking a satire time capsule and providing a chance to think about a show that, on the surface, eschews deep thought. Here are some things to look for as FXX celebrates TV’s most durable nuclear family:

Emmys' Most Memorable Moments

•Drawing a Crowd: The renderings of Homer, Marge, Bart, Lisa and Maggie have morphed over the years from scraggly lined, rough, vertical faces to their current iconic images. Some of the voices are different, too – Homer’s gruff tones, in particular, have softened. The same goes for Seymour Skinner’s voice, which has journeyed from stentorian to beaten-down exasperation.

•Springfield Tourism: Guest appearances, which have grown in frequency over the last 25 years, mark perhaps TV’s greatest cumulative primetime collection of talent since “The Ed Sullivan Show”: Three Beatles, Michael Jackson, Mick Jagger, Liz Taylor, Magic Johnson, Justin Timberlake, Anne Hathaway and Stephen Hawking have lent their voices (and, in many cases, faces) to the show, to name a scant few.

•Treehouse of Delights: The annual Halloween-themed “Treehouse of Horrors” episodes have provided some of the best “Simpsons” moments – ever, as Comic Book Guy would say. Cases in point: parodies of “The Island of Dr. Moreau” (starring Dr. Hibbert), “It’s the Great Pumpkin, Charlie Brown” (with Milhouse perfectly cast as Linus) and “The Twilight Zone” (in which Homer skips through dimensions to the real world – maybe the best Simpson sequence of them all).

•Sentimental Journeys: Forget about the Fox show’s trademark sardonic streak – “The Simpsons” can spur a tear faster than Mr. Burns can release the hounds. The tone was set in the first episode, a Christmas special that brought Santa’s Little Helper to 742 Evergreen Terrace. The death of Lisa’s saxophone hero Bleeding Gums Murphy, the fortuneteller episode in which an adult Lisa (nearly) gets married to a snob and the backstory of Homer’s desertion by his 1960s radical mom (Glenn Close) all show surprising heart and rank among the series’ most memorable installments.

•Having Cows: As much as “The Simpson” mocks sitcoms, it echoes the form – most prominently in catchphrases, some of whose popularity have dissipated with time: “Ay, caramba!” “Don’t have a cow, man.” “Eat my shorts!” “I’m Bart Simpson – who the hell are you?” But “D’oh!” and “Woo-hoo!” have become seemingly permanent additions to the language.

•A Homer Run: The catchphrase continuum starts with Bart, the show’s original breakout character, and extends to Homer, who, for all the citizens of Springfield and celebrity visitors, is the closest thing to being the star of “The Simpsons.” He’ll never replace Bill Cosby as America’s Dad, but he’s the best father Bart, Lisa and Maggie will ever have.

Check out FXX’s clever preview for the marathon below as viewers prepare to take an extended summer vacation to Springfield: